This application claims the priority of the commonly owned copending German patent application Serial No. 100 37 107.8 filed Jul. 27, 2000. The disclosure of the above-referenced German patent application, as well as that of each US and foreign patent and patent application identified in the specification of the present application, is incorporated herein by reference.
The invention relates to improvements in apparatus for damping vibrations between rotary driving and driven parts, such as between the output shaft of an engine or another prime mover and the input shaft of a change-speed transmission in the power train of a motor vehicle. As a rule, such apparatus comprise first and second rotary torque transmitting devices and a torque transmitting and vibration damping unit between such devices.
Torsional vibration damping apparatus of the character to which the apparatus of the present invention pertains are disclosed, for example, in published German patent applications Nos. 199 12 970 A1, 199 09 044 A1, 196 48 432 A1, 196 03 248 A1 and 41 17 584 A1. All such parts or groups of parts in the apparatus of the present invention which are adequately disclosed and illustrated in the above-enumerated and other published German patent applications as well as in US and foreign patents granted to the assignee of the present application and/or others will be described only to the extent necessary to readily locate the relevant references for additional disclosure (if necessary).
A drawback of presently known torsional vibration damping apparatus is that they are not effective under any and all circumstances which arise in torque transmitting machines, assemblies or apparatus, as well as that they are in part too bulky, complex and expensive. Moreover, many (if not all) presently known torsional vibration damping apparatus are overly sensitive to the presence and influence of foreign matter, mainly or often because their sensitive parts are not adequately shielded against penetration of impurities and/or against uncontrolled escape of lubricant.
An object of the present invention is to enhance the simplicity and reliability as well as to reduce the initial and maintenance cost of torsional vibration damping apparatus, for example, of apparatus which can be put to use in the power trains of motor vehicles.
Another object of the invention is to provide torsional vibration damping apparatus which can be installed in existing power trains as superior substitutes for conventional apparatus of such character.
A further object of the invention is to provide novel and improved means for reliably confining lubricant in the enclosure for the torsional vibration damper in the above outlined apparatus.
An additional object of the invention is to provide novel and improved means for shielding the sensitive constituents of torsional vibration damping apparatus from adverse influences of dust and/or other foreign matter.
Still another object of the instant invention is to provide novel and improved seals for use in torsional vibration damping apparatus of the above outlined character.
A further object of the invention is to provide a power train, particularly for use in a motor vehicle, which embodies a torsional vibration damping apparatus of the above outlined character.
Another object of the invention is to provide a novel and improved apparatus which is designed to transmit torque between the rotary output element of the engine and the rotary input element of the transmission in the power train of a motor vehicle, such as a passenger car, a truck, an SUV and/or others.
The invention resides in the provision of an apparatus for damping vibrations between coaxial rotary input and output elements, such as between the crankshaft or the camshaft of an internal combustion engine and the input shaft of the transmission in the power train of a motor vehicle. The improved apparatus comprises a first rotary torque transmitting device which is coaxial with and is arranged to receive torque from the output element, and a second rotary torque transmitting device which is coaxial with and is arranged to transmit torque to the input element. One of the two torque transmitting devices comprises at least two sidewalls which are rotatable with each other and bound (such as flank) an annular chamber having a sealed radially outer part and a radially inner part which is sealed in accordance with an important feature of the present invention. The apparatus further comprises a partition including a radially outer section in the chamber and a ring-shaped radially inner section extending substantially radially inwardly beyond the inner part of the chamber and being connected with the other of the two torque transmitting devices, energy storing means provided in the chamber and arranged to yieldably oppose rotation of the one torque transmitting device and the partition (i.e., the other torque transmitting device) relative to each other, and means for sealing the inner part of the chamber. Such sealing means comprises at least one annular carrier borne by one of the sidewalls and a deformable annular sealing lip provided on the carrier and sealingly engaging the ring-shaped inner section of the partition. The carrier consists of a first material, and the lip consists of a different second material (i.e., of a material other than that of the carrier).
The lip sealingly engages a first side of the inner section of the partition and the sealing means can further include an additional carrier which is borne by the other sidewall as well as an additional deformable annular sealing lip provided on the additional carrier and sealingly engaging a second side of the inner section of the partition. The additional carrier consists or can consist of the aforementioned first material, and the additional lip consists or can consist of the second material. The carriers and the lips are (or can be) respectively mirror images of each other with reference to a plane which is normal to the common axis of the torque transmitting devices.
Each carrier can include radially inner and radially outer portions and each lip can be provided on the radially inner annular portion of the respective carrier.
Each lip can be of one piece with the respective carrier.
Each lip is or can be deformed as a result of sealing engagement with the ring-shaped inner section of the partition, and each lip can include at least one at least substantially frustoconical or at least substantially dished portion at least in the underformed condition of such lip.
Each lip can include an annular portion which is in sealing engagement with the inner section of the partition and is offset relative to the respective carrier in the direction of the common axis of the torque transmitting devices.
Each lip and/or the respective carrier can include at least one annular bead at the respective sidewall. Each bead is deformable and can sealingly engage and is deformed by the respective sidewall.
The second material (of the lip or lips) is or can be elastic so that each such lip can be deformed by the respective sidewall in the direction of the common axis of the torque transmitting devices.
At least the one torque transmitting device is normally rotatable at a plurality of different speeds and each lip is or can be configurated to undergo progressing deformation under the action of centrifugal force in response to increasing speed of the one torque transmitting device. Each such lip is or can be arranged to undergo progressing deformation axially and/or radially of the sidewalls in response to increasing rotational speed of the one torque transmitting device.
Each carrier can be fixedly secured (such as welded or otherwise bonded) to the respective sidewall. The sealing means can include separately produced means for connecting each carrier to the respective sidewall. Such connecting means can include one or more rivets, e.g., rivets which are of one piece with the respective carrier and/or with the respective sidewall.
The material of the lip or lips can be a plastic material, e.g., an elastomer including rubber, fluorocaoutchouc, fluorosilicon caoutchouc, silicone caoutchouc or the like.
The material of each lip can have a Shore hardness of between about 50 and 90, preferably at least close to 75.
The sealing means of the improved apparatus can further include a film of a suitable friction reducing material (such as a lacquer, especially PTFE) which is applied at least to the radially inner section of the partition and is contacted by the lip or lips of such sealing means.
The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved torsional vibration damping apparatus itself, however, both as to its construction and the modes of assembling, installing and utilizing the same, together with numerous additional important and advantageous features and attributes thereof, will be best understood upon perusal of the following detailed description of certain presently preferred specific embodiments with reference to the accompanying drawings.